This is a list of all known competitors, and some brief description and opinions about them,
along with hyperlinks so you can make up your mind for yourself.
If you have any additions, please let me know and I will add them.
Similarly, if you want to revise my characterizations.
Also, keep in mind, my comments are generally NOT well researched.
If you really want to know about these particular products, contact the vendors themselves.

Obviously vastly much more functionality. Also, requires much more disk space and system resources. More expensive. Very heavy, busy, wasteful of screen real-estate user interface (if you could all the ribbon bars, and title bars, and icons, and pallets that come up by default, on a 13 inch screen, less than half is dedicated to actually seeing the text!). Word is ... not parsimonious. But it is cross-platform, and the reference against which all others are compared.

I tried version 0.7.7 (991222).
It looked very interesting. But it was EXTREMELY buggy. I only tried the Win32 build.
But it crashed so often that I was hard pressed to evaluate it. It maybe that alot of the problem
had to do with RTF. I was testing it reading RTF docs. Reading the native format docs they provided
seemed to work OK. But most menu commands brought up "Not Yet Implemented" dialogs. Keep an eye out for future releases.
I have since been told that the release 1.0.3 is out, and is much less buggy. I've not had the chance
to look at it myself.